A few of us on RCSCALEBUILDER.COM are working on a Ho 229 design together. We are starting with a slope glider (PSS) but want to build an EDF version for hand or bungee launch. Some are dreaming of an ROG version with scale retracts, etc. Not sure if this is practical with current EDF technology.

I'm curious, how did you arrive at the wingspan to fan size figures below? Is this because of thrust requirements, or does it have to do with scale size of the openings?

Gary

Originally Posted by Heiner

Tim,
if you choose the Het 3W at 3s1p you just draw 20A each in the minifan.
30A each at 4s1p ...........

Should have mentioned -- the reason I ask is that we are building a 66 inch span Ho IX V1 glider I'm hoping to do the first EDF model in the same span. The scale jet inlet and exhaust openings are about 2 inches at this scale. I'd like to stay as close to the scale inlet size as possible. The Wemotec micro fan is about the right size, but some have expressed doubts two of them can produce enough thrust. Has anyone tried tapered tubes? In other words, 'cone' shaped inlet and exhaust tubes with the 'choke' points at the ends. Or would this rob any extra thrust provided by the larger diameter fan?

I really don't like the look of scale jets with ridiculously oversized intakes. Ruins the scale looks and almost makes the model pointless, for me at least.

Speaking of tubes, what are people using? Are there ready-made lightweight tubes available for EDF? I haven't seen anything on the net.

Should have mentioned -- the reason I ask is that we are building a 66 inch span Ho IX V1 glider I'm hoping to do the first EDF model in the same span. The scale jet inlet and exhaust openings are about 2 inches at this scale. I'd like to stay as close to the scale inlet size as possible. The Wemotec micro fan is about the right size, but some have expressed doubts two of them can produce enough thrust. Has anyone tried tapered tubes? In other words, 'cone' shaped inlet and exhaust tubes with the 'choke' points at the ends. Or would this rob any extra thrust provided by the larger diameter fan?

I really don't like the look of scale jets with ridiculously oversized intakes. Ruins the scale looks and almost makes the model pointless, for me at least.

Speaking of tubes, what are people using? Are there ready-made lightweight tubes available for EDF? I haven't seen anything on the net.

Gary

Gary,

Although i deal with a lot of EDF models I'll never claim to be an authority. I can say, however, that the thrust of the Wemotec Micro fans is limited, at best. I have a 39 oz F-14 with two Microfans using pretty good 6000KV motors, and I'm lucky if I can get 1.5 pounds thrust. Keep in mind that it takes a bit of serious battery to attain this. Having said that, this particular model was never designed for fans to begin with so the ducting is far less than optimal. However, there are scale jets with designed for EDF with scale intakes that can really put out, these using Minifans or Midifans. I have a larger F-14 that will probably weigh in about 7-8 pounds and I have no issue with it being able to easily fly with two minifans.

For duct tubes, people use almost anything from Krispy Kreme box material to heavy paper. Personally, I use drafting mylar. The main concern is that the duct forward of the fan will not collapse and that the exhaust tube will not blow apart...both issues easily dealt with.

Personally, if I were to build a Horton it would be sized, at the very least, to take advantage of the Minifan. With the new motors, batteries, and fans today the limitations of scale intakes are becoming less and less. There are many people on 'the other' forum that are extremely well versed with such matters and I would suggest you try them out to get the information you require. I know that *I* would.

Hi Guys, just thought I'd mention these Horten plans, posted under "Builders Techniques" a couple of months ago. http://www.bellimelgroup.com/products.htm
Don't know if they're of any use to you but worth a look!
Ron

We are now looking at using the Wemo mini-fans and upsizing the model (Ho 229) to 1/8 scale (82" span). These fans with the right motors/batteries and a light airframe (no LG, etc.) should be a speedy combination. We have obtained the original Horton airfoil data (all 19 stations!) along with all of the other relevant aerodynamic data, and plan to build a prototype that is precision scale. We *do* expect there to be issues. We plan to fly this second design also as a slope glider first.

Hi Guys, just thought I'd mention these Horten plans, posted under "Builders Techniques" a couple of months ago. http://www.bellimelgroup.com/products.htm
Don't know if they're of any use to you but worth a look!
Ron

Ron,

I emailed the fellow who drew up and sells these plans with a few questions as I intended to purchase a set. He never replied, so I dropped the idea. He has/had a couple of threads on RC Groups forums, but it seemed like he never wanted to answer some direct questions about his planes. They look good, but he doesn't appear to really want to sell the plans, IMHO.

Arthur Bentley has a lot of them, they may help to create a very scale HO-229 V3.

Heiner

I can't imagine a more accurate source of information other than having the real thing right in front of you. I tried to get information on the one in the US at the Smithsonian Institute, but apparently it's packed away in some big warehouse (makes me think of the ending scene in the first Indiana Jones movie) and not obtainable by mere mortals. On the other hand, the fellow I spoke to there gave me Bentley's name and recommended his work highly. What's even better about the Bentley drawings is that they can be ordered in different sizes making plans development a lot easier.

have you fellas seen this site http://home.planet.nl/~otten100/ very interesting indeed. this man is also making an 82 inch version. it looks like he has collected quite an array of relevent documentation and has tested a PSS version of the model.

Heiner i am certainly interested in a minfan version. i couldnt afford a midifan setup

I went crazy several months back trying to get some information on that model, since it's about the nicest I've yet to see. I got absolutely nowhere. If anyone can locate the owner and get some information it would be great. As I recall the email adresses given were no longer valid, and attempts to find the original builder or the new owner were fruitless.

Arthur Bentley made new drawings from many information he could collect during 40 years. He visited the Smithsonian Institute and he has also original Horten production drawings from the German Museum in Munich, the drawings the Americans gave back to Germany after WWII. Arthur Bentley worked for an English airplane company, so you will be surprised what detailed drawings you can order from him!